Vein harvesting system and method

ABSTRACT

A tissue illumination system and a method for harvesting a section of a blood vessel from a patient&#39;s body for further use. The tissue illumination system includes a light catheter inserted into a lumen of the blood vessel section to illuminate the vessel section and vessel side branches with an intensity which is visible to the physician from an exterior of the vessel section and also includes a viewing element insertable into the lumen and capable of viewing the illuminated vessel section. The tissue illumination system also includes at least one tool insertable into the lumen and used to harvest the vessel section.

This application is a continuation of application Ser. No. 13/113,369,filed May 23, 2011, which is a continuation of application Ser. No.12/241,316, filed Sep. 30, 2008, now U.S. Pat. No. 7,959,553 B2, issuedJun. 14, 2011, which is a continuation of application Ser. No.11/787,323, filed Apr. 16, 2007, now abandoned, which is a continuationof application Ser. No. 10/780,370, filed Feb. 17, 2004, now U.S. Pat.No. 7,211,040, issued May 1, 2007, which is a continuation ofapplication Ser. No. 10/391,148, filed Mar. 18, 2003, now U.S. Pat. No.6,705,986, issued Mar. 16, 2004, which is a continuation of applicationSer. No. 09/715,382, filed Nov. 17, 2000, now U.S. Pat. No. 6,558,313,issued May 6, 2003, hereby incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

This invention relates to a system and a method for harvesting agenerally cylindrical tissue structure from the body of a patient. Moreparticularly, the invention is directed to a system and a method forharvesting a section of a blood vessel from a patient.

BACKGROUND OF THE INVENTION

In certain circumstances it is desirable to remove sections of tubulartissue structure from a patient's body. Such tissue may be used inanother part of the patient's body, may be transplanted into a secondpatient's body or may be discarded. As used herein, the term “tubulartissue structure” includes blood vessels, tendons, bile ducts, nervesand any other similar tissue formation which is generally tubular instructure and capable of being separated from surrounding tissue.Although the invention herein will be discussed in terms of harvestingblood vessels it should be understood that the apparatus and methoddescribed are equally applicable to harvesting other solid orcylindrical tubular tissue structure.

Vein harvesting is commonly done in connection with coronary arterybypass surgery. The saphenous vein is a subcutaneous vein which is oftenused for coronary artery bypass grafting, infra-inguinal bypass graftingand vein-vein bypass grafting. Other vessels may also be used includingthe internal mammary artery, the radial artery, and/or the lessersaphenous vein. Previously, it has been necessary to make an incisionalong the full length of the vein section to be removed. The vein isthen freed by severing and ligating the branches of the vein, afterwhich the section of the vein can be removed from the patient. Thefull-length incision must then be closed, for example by suturing orstapling. Obviously, the harvesting of the vein in this manner leavesdisfiguring scars which are cosmetically undesirable. Additionally, thelarge incision creates a risk of infection to the patient and may notheal properly, especially with those patients who have poor circulationin their extremities. Such an incision may create a chronic non-healingwound, requiring significant and costly medical treatment.

Devices for harvesting a section of a blood vessel without creating afull-length incision have been suggested and include that described inU.S. Pat. No. 4,793,346 (Mindich) and UK Patent No. GB 20 82 459A. Thesepatents describe methods that use incisions at either end of the bloodvessel to be harvested. Such devices and methods can be disadvantageousbecause greater blood loss than is necessary can result. These devicesmay also remove more tissue than is necessary because the size of thecutting device is not readily adaptable to the changes in the size ofthe blood vessel. In addition, these patents describe techniques whichhave a high probability of damaging the vessel, making it unsuitable foruse as a vascular conduit.

In U.S. Pat. No. RE 36,043 (Knighton), a device and a method for veinremoval are disclosed which solve some of the problems associated withthe use of prior art devices. Knighton discloses an endoscope having alumen extending longitudinally through the scope body. The endoscopeincludes means for viewing an area adjacent the distal end of the lumen.The lumen has a lateral dimension large enough to accommodate the bloodvessel being harvested and at least one tool for use in harvesting theblood vessel. A first end of the blood vessel section to be harvested isexposed through an incision in the patient's body. A dissecting tool anda gripping tool are inserted through the lumen of the endoscope and usedto dissect the blood vessel away from the surrounding connective tissueof the patient's body. Additional tools are provided for use through thelumen of the endoscope to remove body fluids and coagulate bleedingtissue, to ligate and sever side branches from the blood vessel to beharvested, and to ligate and sever a distal end of the blood vessel tobe harvested when a desired length of blood vessel has been dissected.Only a small incision in the patient's body is necessary to harvest arelatively long length of blood vessel in a precise and controlledmanner using this device and procedure.

U.S. Pat. No. 5,772,576 (Knighton et al.) also describes a device andmethod for vein removal. The device has one or more lumens extendingthrough a body portion. One lumen is sized to accommodate a blood vesseland at least one tool for use in removing the vessel. The device mayalso include viewing means so that the operator may remotely view anarea adjacent the distal end of the body portion. The device protectsthe vessel being removed from damage by the tools used in the procedure,which is critical since the blood vessel is destined for reuse (as inarterial bypass). In addition, a single operator can use the device.

In commonly assigned, co-pending application Ser. No. 09/715,665,(Knighton et al.) filed Nov. 17, 2000, entitled “Vein Harvesting Systemand Method”, the entirety of which is incorporated herein by reference,a system that is easier to use and minimizes damage to a blood vessel isdescribed. In this system, a multi-lumen tube is used in conjunctionwith a housing having a removable lower portion. The housing provides aworkspace for the removal of a blood vessel and the multi-lumen tube andassociated tools provide a means to see and to remove a desired lengthof vein and cut and cauterize any vein side branches while minimizingdamage to the vein and trauma to the patient. An additional problem withpresent technology is determining the course of the main saphenous trunkversus a large side branch. The course of the main vein would also bebeneficial to see well ahead of the dissection to facilitate the speedof dissection.

The need also exists for a vein harvester having a variable length andfurther having tools that would be easier and more convenient to use.The tools typically used in the current procedures tend to be long anddifficult to control. Having tools with a variable length would allowfor an easier, more precise, and more rapid procedure.

SUMMARY OF THE INVENTION

This invention is a system and a method for the harvesting of a bloodvessel. The system comprises an expandable hood to make a workspace forextraction of the vein and an extendible or telescoping device havingdesired tools at its distal end. The tools are activated at the proximalend of the telescoping device. The method comprises illuminating thedissection area via a light catheter that is inside the lumen of theblood vessel and deploying the telescoping device to the length desiredto dissect the vein from surrounding tissue.

In a first aspect the invention is a method of harvesting a section of avessel from a human or animal body. The method comprises exposing thevessel section to be harvested through an incision in the body;providing a light source; placing the light source in the lumen of thevessel, the light source being sufficient to illuminate substantiallythe entire vessel section and vessel side branches extending from thevessel section with an intensity which is visible from an exterior ofthe vessel section; dissecting the vessel away from surroundingconnective tissue of the body with a dissecting tool inserted throughthe incision; viewing the dissection of the vessel with a viewingelement inserted through the incision; cutting the vessel at proximaland distal ends of the vessel section; and removing the vessel sectionfrom the patient's body. The vessel section may be exposed through firstand second incisions with the dissecting tool and viewing elementinserted through the first incision and the light source placed in thevessel lumen through the second incision. The first incision may be madeover a proximal end of the vessel section and the second incision over adistal end of the vessel section. The method may further compriseproviding a telescoping member having first and second substantiallycylindrical segments, the second segment sized to fit within a lumen ofthe first segment, the telescoping member being adjustable in lengthfrom a fully collapsed position where the second segment is containedsubstantially within the first segment to a fully extended positionwhere the second segment is substantially removed from the firstsegment, the telescoping member having the dissecting tool connected toa distal end of the second segment, and inserting the telescoping memberthrough the incision. The step of proving the telescoping member maycomprise providing a telescoping member wherein the viewing element andtool used to cut the vessel are connected to the distal end of thesecond segment. The method may comprise providing a hood memberconfigured to be moveable from a first closed position to a second openposition; inserting the hood member through the incision, adjacent thevessel; and creating a working space adjacent the vessel by opening thehood member from the first closed position to the second open position.

In another aspect the invention is a system for harvesting a section ofa vessel from an incision in a human or animal body. The systemcomprises a light source sized and configured to be inserted into alumen of the vessel, the light source being sufficient to illuminatesubstantially the entire vessel section with an intensity which isvisible from an exterior of the vessel section; a viewing elementconfigured to be insertable through the incision and capable of viewingthe illuminated vessel section; and at least on tool used to harvest thevessel section, the at least one tool being sized to be inserted throughthe incision. This system may include a telescoping member having firstand second substantially cylindrical segments, the second segment sizedto fit within a lumen of the first segment, the telescoping member beingadjustable in length from a fully collapsed position to a fully extendedposition by slidably adjusting the extent to which the second segment iscontained in the lumen of the first segment, the telescoping elementhaving a dissecting tool connected thereto. The viewing element may beconnected to the telescoping member. A dissection element connected tothe telescoping member may also be included. A hood member configured tobe moveable from a first closed position to a second open position maybe included in the system. The hood member is sized to be insertedthrough the incision in the closed position and placed adjacent thevessel section. The hood is further configured to create a working spaceadjacent the vessel when moved to the open position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a portion of a patient'sbody prepared for insertion of the device of the invention.

FIG. 2 is a perspective view of the expandable hood in its retractedposition over the vein to be harvested.

FIG. 3A is a perspective view of the telescoping device of the presentinvention in its retracted position.

FIG. 3B is a perspective view of the telescoping device of the presentinvention in its fully extended position.

FIG. 3C is an exploded view of the distal end of the telescoping deviceof FIGS. 3A and 3B.

FIG. 4A is a partial cross-sectional view of a portion of a patient'sbody illustrating insertion of the light catheter into the vein to beharvested.

FIG. 4B is a partial plan view of the light catheter of the presentinvention.

FIG. 5A is a sectional view along line 5-5 of FIG. 2.

FIG. 5B is a view similar to FIG. 5A but with expandable hood in itsfully expanded position.

FIG. 5C is a bottom view of the expandable hood.

FIG. 6 is a partial view of the dissection process showing telescopingdevice used to dissect vein V and light catheter in the lumen of vein V.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a system and a method for harvesting a tubulartissue section such as a section of a vessel from a patient's body foruse in another part of a patient's body or for transplanting into asecond patient's body. For example, a section of the saphenous vein maybe removed for use in coronary bypass surgery. The saphenous veintravels along the medial side of the foot, leg, and thigh, where itjoins with the femoral vein near the groin. Although specific referenceherein is made to harvesting a section of saphenous vein it should beunderstood that the invention could be used to harvest other tubulartissue sections from human or animal bodies.

The terms “distal” and “proximal” as used herein refer to the method ofuse of the system. “Proximal” refers to a location closer to thephysician and “distal” refers to a location farther from the physician.“Upper” and “lower” also are terms that refer to an orientation withrespect to the use of the device, that is, relative to the physician.

In the method of this invention, the patient is first prepared forremoval of the vein. The method is suitable for removal of any vein ortubular tissue structure; however, the invention is exemplified byreference to the saphenous vein. A first incision is made in the areafrom which the vein is to be harvested. For example, the incision ismade in the groin area for harvesting the saphenous vein. A second,distal, incision is also made. For example, this distal incision will benear the knee (either above or below the joint) if the longest sectionpossible of vein is needed. An expandable hood is inserted through thefirst incision and positioned over the top of the saphenous vein. Thisserves to lift surrounding tissue away from the vein. Then theexpandable hood is expanded to create a space sufficient to permit theuse of tools so that the vein may be dissected.

At the site of the distal incision, the vein or a side branch is cut anda light catheter (e.g., a fiber optic cable) is inserted into the lumenof the vein to illuminate the area of dissection and display the lumenof the vein. A device that is extendible, referred to as a telescopingdevice, is provided with tools at its distal end and is inserted throughthe first incision and under the expandable hood. The telescoping deviceprovides the means to dissect the vein from the connective tissue and tocut and clip or cauterize any vein side branches. The telescopic devicehas a viewing fiber optic cable connected to a monitor so that thephysician can see the dissection area. In addition, suction may beprovided to remove blood and debris from the dissection field.Irrigation of the area of the vein with saline also may be providedthrough the telescoping device.

Turning now to the Figures, the system and method of the invention areillustrated. After proper preparation of the incision site, thephysician makes a small incision I′ (e.g., about 3 cm long) over theproximal aspect of the blood vessel to be harvested. FIG. 1 illustratesthat incision I′ is made in the region above the saphenous vein V. VeinV typically has side branches V′. The incision is made in the skin (S)and through various layers such as scarpa's fascia (F) and subcutaneousfat layer (FL). Underneath the saphenous vein is fascia (F′) and muscle(M). For the sake of simplicity, such layers are not shown in FIGS. 2,3A, 3B, 5A, 5B, and 6.

As shown in FIG. 1 the physician inserts a finger identified asreference numeral 1 to separate the various tissue layers from thesaphenous vein and to make sufficient room to insert expandable hood 10into incision I′. Hood 10 is inserted into the incision and moveddistally a desired length of the saphenous vein. Optionally, a bluntdissector could be used to initially open a small space to allow foreasier insertion of the hood. FIG. 5A is a cross-sectional view alongline 5-5 in FIG. 2. In this position a portion of the proximal end ofhood 10 extends from the incision. Hood 10 is now in a first closed orcontracted position. Then hood 10 is expanded, or opened, as shown incross-section in FIG. 5B. Hood 10 is opened to a second expandedposition by removing pin 11 from the proximal end of the hood. Thephysician does this by simply grabbing and pulling on a proximal portionof the pin which extends from the hood. The hood is comprised of metalor plastic which is biased in the open or expanded direction. The pin 11extends through holes in teeth 50 and 52 located on first and secondlateral edges of the hood. As best seen in FIG. 5C in the closedposition the teeth 50 and 52 mesh and are held together by the pin sothat the hood remains in the closed position. Removal of pin 11 releasesthe lateral edges allowing the hood to expand to its open or expandedposition. The movement of the hood from the closed to open positioncreates a sufficient working space above the saphenous vein for toolsused in the harvesting procedure. Once the hood is expanded the site isready to receive telescoping device 20.

Telescoping device 20 has proximal end 12 and distal end 14 and isconstructed of a rigid material such as metal or plastic. Device 20 isshown in FIGS. 3A and 3B as having two telescoping segments, 22 and 24.It is to be understood that more telescoping segments could be used inthe system of this invention depending on the length and degree ofarticulation desired. The length of one segment is shown as being aboutthe same as the length of another segment, although it is also to beunderstood that the segments may have lengths different from oneanother.

Device 20 is advanced along the top of the saphenous vein underexpandable hood 10 by extending the telescoping segments. FIG. 3A showsthe device in a collapsed or non-extended condition with a substantialportion of segment 24 lying within segment 22. Segment 24 is sized to befriction fit within segment 22. The vein harvesting procedure is usuallybegun with the device in the collapsed position. As additional length isdesired the device is withdrawn from the incision far enough so that thephysician can grasp the two (or more) sections and pull them apart. Thephysician may adjust the relative position of the segments until thedevice has a desired length. The segments are friction fit in a mannerthat maintains the desired position between segments so that the devicecan continue to be used to dissect the vessel without axial slippage ofthe sections relative to one another. It will be appreciated that othermeans of extending the telescoping sections could be used such as usinga worm gear and stepper motor. The segments are extended as the vein isdissected to the desired length, which is dependent upon the length ofthe vein to be dissected. As best seen in FIGS. 3A and 3B aspring-loaded dimple 54 on the proximal portion of segment 24 mates witha hole 56 in the distal portion of segment 22 to act as a positive stopof the relative movement between the sections. Alignment of dimple 54with hole 56 may be accomplished by providing a longitudinal groove 58on the inner surface of segment 22 in which dimple 54 is positioned. Thelongitudinal groove maintains the axial alignment of the segments as thedevice is extended. It will be apparent to those of skill in the artthat other means of limiting the axial movement of the segments withrespect to one another could be provided.

In FIG. 3A the device is shown in the collapsed position while in 3B thedevice is shown in the fully extended position. FIG. 3C shows a distalend view of the device and the various tools and viewing means connectedthereto. Associated with telescoping device 20 are appropriate tools atdistal end 14 which include vein dissector 32 and cutting means, such asbipolar scissors 34. Inserted through proximal end 12 is suction line36, which is contained within central lumens of segments 22 and 24 andwhich provides a means to remove blood, debris, and irrigation fluidsuch as saline from the surgical area. Actuator 38 is operably connectedthrough flexible line 60 to the bipolar scissors 34 and permits theiroperation at the desired time. Fiber optic line 40 is provided to detectthe light provided by the light catheter in the vein. The fiber opticline is connected to a monitor (not shown) so that the physician can seethe dissection area. An irrigation line 37 is provided and connected toan irrigation source (not shown) at one end and to the distal end of thetelescoping device at the other. Lines 36, 37, 40, and 60 extend fromthe proximal end of the device and are contained within the lumens ofsegments 22 and 24. Lines 36, 37, 40, and 60 are connected at the distalend of segment 22.

Vein dissector 32 is fixed at the end of segment 22, preferably at acircumferential position spaced approximately 180° from the position atwhich line 60 and bipolar scissors 34 are fixed. The vein dissector 32is provided with an open loop having an opening 62 so that it can beslipped onto and off of the vein as desired. For example, duringdissection of the vein if a side branch is encountered the veindissector can be removed and the device rotated 180° so that the bipolarscissors can be used to cut and coagulate the side branch. The device isthen rotated back and the vein dissector slipped over the vein andadvanced in the distal direction so the dissection process is continued.Although a spacing of 180° is preferred between the vein dissector andbipolar scissors it will be appreciated that other spacing could be usedso long as the spacing is sufficient to allow the tools to be usedwithout interference from one another. Vein dissector 32 includes ablunt tip portion 33 which is used as an additional means of dissectingtissue from the vein and as a probe. This vein dissector may be a fullcircular dissector or, more preferably, a loop dissector as shown, whichpermits the vein to be dissected and removed from the dissector any timeit is desired.

Cutting means 34 preferably is a bipolar scissors. Such scissors areconfigured to cut and cauterize size branches V′ of the vein as they areencountered during the dissection of vein V. Alternatively, any cuttingmeans can be used and appropriate ligation means (such as a suture or aclip) also can be used.

The actuator is adapted to operate cutting means 34, preferably bipolarscissors, which cuts and cauterizes side branches V′ of vein V as thedissection proceeds. The dissection process proceeds distally alongblood vessel V. The operator of the device views the dissection process(occurring at the area immediately adjacent distal end 14 of telescopingdevice 20) through the optical viewing device/detector 40 and associatedmonitor. Optionally, a saline infusion line 37 may be included to ensurethat the lens at the distal end of the fiber optic line remains clear.

As seen in FIGS. 4A and 4B light catheter 42 is inserted via distalincision I″ into the saphenous vein at the distal end. Alternativelycatheter 42 may be inserted into a large side branch located near thedistal end of the vein. Light catheter 42 is moved proximally to theproximal end of the vein in the direction of incision I′. Theconstruction of catheter 42 is best seen in FIG. 4B which is a partialview of catheter 42. Catheter 42 includes a transparent outer sheath 64comprised of a material capable of transmitting light along the entirelength of the catheter. A fiber optic cable 66 is connected to a lightsource 44. The catheter is constructed so that when inserted into a veinit will light up substantially the entire vein section being harvestedand side branches along the length of the catheter. It should beunderstood that any light source sufficient to illuminate light catheter42 along its length would be suitable for use in this invention. Forexample, light transmissive fluid or an internal chemical light sourcecould be used. A heparin and/or saline source 46 is connected to thelumen of catheter 42 via line 48. Holes are provided in catheter 42 sothat heparin and/or saline can be injected into the vein.

During a typical saphenous vein harvesting procedure the vein harvestingsystem is used as follows. A first incision I′ is made over the groinarea. A second distal incision I″ is made above or below the kneedepending on the length of vein needed. Expandable hood 10 is insertedinto incision I′ over the saphenous vein. The hood is expanded to createsufficient space to use the telescoping device including its dissectingand cutting tools. At the second incision the saphenous vein or a sidebranch is cut and light catheter 42 is inserted into the saphenous vein.Light catheter 42 is advanced in the proximal direction to a positionsufficient to light the saphenous vein and side branches between thearea of the first and second incisions. The telescoping device 20 isinserted beneath the hood through the first incision after the physicianhas exposed the saphenous vein with his or her finger. The saphenousvein is inserted into the vein dissector 32 through slot 62. Theprocedure is usually started with the telescoping device fully collapsedalthough the segments may be manipulated to lengthen the device ifdesired.

The device is advanced under direct vision of the physician until nolonger visible by eye, after which the physician views the process onthe monitor. By utilizing light catheter 42 the physician's view of thedissection and cutting process is improved over prior art procedureswhere the light source is external to the vein. FIG. 6 shows the use ofthe telescoping device during the dissection of a vein containing thelight catheter.

When a side branch is encountered the vein dissector is removed from thevein and the telescoping device rotated so that the bipolar scissors (orother cutting means) can be used to cut and coagulate (or clip) the sidebranch. The device is then rotated and the vein dissector slipped overthe vein so the dissection process can continue.

When the telescoping device has been inserted to a distance where itbecomes necessary to lengthen the device to continue the dissection thephysician withdraws the device through the incision far enough so thatthe sections can be grasped and pulled apart to lengthen the device adesired amount. The device is then moved distally and the dissectionprocess continued.

When a sufficient length of the vein has been dissected the device isremoved from the first incision and the vein is cut at the location ofthe first and second incisions and then removed, usually from the firstincision.

It should be appreciated that the light catheter could be insertedthrough the same incision as the telescoping device and inserted intothe vessel through a side branch.

Although particular embodiments have been disclosed herein in detail,this has been done for purposes of illustration only, and is notintended to be limiting with respect to the scope of the claims. Inparticular, it is contemplated that various substitutions, alterations,and modifications may be made to the invention without departing fromthe spirit and scope of the invention as defined by the claims. Inaddition, it should be understood that although the various componentsand tools of this invention have been disclosed as a system it ispossible and advantageous to use them separately. For example, theexpandable hood of this invention could be used advantageously withknown vein harvesting tools to create working space therefore. Thetelescoping device could be used without the expandable hood and couldbe used without the light catheter if provided with a light source.Further, the light catheter could advantageously be used to improve theuse of prior art vein harvesting tools and techniques, the effectivenessof which would be enhanced by more clearly being able to visualize thevessel and side branches.

What is claimed is:
 1. A system for harvesting a section of a vesselfrom an incision in a human or animal body comprising: a catheter sizedand configured to be inserted into a lumen of the vessel, the catheterbeing configured to illuminate an entire length of the vessel sectionwith an intensity which is visible from an exterior of the vesselsection; a viewing element configured to be insertable through theincision and capable of viewing the illuminated vessel section; at leastone tool used to harvest the vessel section, the at least one tool beingsized to be inserted through the incision; and a telescoping memberhaving first and second substantially cylindrical segments, the secondsegment sized to fit within a lumen of the first segment, thetelescoping member being adjustable in length from a fully collapsedposition to a fully extended position by slidably adjusting the extentto which the second segment is contained in the lumen of the firstsegment; and a hood member movable from a first closed positioned to asecond open position, the hood member being sized to be inserted throughthe incision in the closed position and placed adjacent the vesselsection, the hood member being shaped to create a working space adjacentthe vessel when moved to the open position.
 2. The system of claim 1,wherein the viewing element is connected to the telescoping member. 3.The system of claim 2 further comprising a dissection element connectedto the telescoping member.